feat(icons): added mail-clock icon (#4722)

* Added icons/mail-clock.svg

* Added icons/mail-clock.json

* Add use cases to mail-clock.json

Added use cases for mail-clock icon.

* Apply suggestions from code review

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

---------

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

icons/mail-clock.json

@@ -0,0 +1,36 @@
+{
+  "$schema": "../icon.schema.json",
+  "contributors": [
+    "colebemis",
+    "karsa-mistmere",
+    "ericfennis"
+  ],
+  "use-cases": [
+    "Represents scheduled communication",
+    "Represents send later icons",
+    "Indication scheduled mail",
+    "Indication delayed delivery features in messaging, email, and productivity tools"
+  ],
+  "tags": [
+    "email",
+    "message",
+    "letter",
+    "unread",
+    "scheduled",
+    "delayed",
+    "sendlater",
+    "delivery",
+    "reminder",
+    "pending",
+    "outgoing",
+    "timer"
+  ],
+  "categories": [
+    "text",
+    "account",
+    "mail",
+    "time",
+    "notifications",
+    "communication"
+  ]
+}

icons/mail-clock.svg

@@ -0,0 +1,17 @@
+<svg
+  xmlns="http://www.w3.org/2000/svg"
+  width="24"
+  height="24"
+  viewBox="0 0 24 24"
+  fill="none"
+  stroke="currentColor"
+  stroke-width="2"
+  stroke-linecap="round"
+  stroke-linejoin="round"
+>
+  <path d="M16 14v2.2l1.6 1" />
+  <path d="m22 7-.759.484" />
+  <path d="M6.835 20H4a2 2 0 01-2-2V6a2 2 0 012-2h16a2 2 0 012 2v2" />
+  <path d="M7.605 10.567 2 7" />
+  <circle cx="16" cy="16" r="6" />
+</svg>